Monitoring devices (liquid crystal monitors) for computers and television receivers (liquid crystal TV) are sold on the market as practical product examples of display devices (liquid crystal display devices) using electro-optical characteristics of liquid crystal.
The liquid crystal display device of active matrix type, which is the mainstream presently, has a pixel structure where a switching element that is called a thin film transistor (TFT) is provided for each pixel. The technique to manufacture such a display device is developed by combining a photolithography process using a photomask, and a film forming or etching process using vacuum equipment and the like properly, similar to a manufacturing technique of a semiconductor integrated circuit.
A manufacturing process like this includes a process in which a film of a conductive material, an insulator, a semiconductor film and the like is formed by sputtering or chemical vapor deposition (CVD), a process in which an intended pattern is made by soaking a resist film in a developing solution after applying a photosensitive resist film on the film and exposing it through a mask by using projection photolithography equipment, and a process in which etching is performed using a solution or an active reactive gas, with these processes combined and performed repeatedly.